Brake Booster

Brake Booster

• Check the brake boost vacuum first if there are complaints regarding the brake booster. Refer to => [ Brake Booster Vacuum System, Checking ] Testing and Inspection.

Special tools, testers and auxiliary items required

• Brake Charger/Bleeder Unit (VAS 5234)

• Torque Wrench 5-50 Nm (V.A.G 1331)

• Engine Support Bridge (10 - 222 A)

Removing

- If the vehicle has a coded radio, get the radio code from the customer before beginning.

- Disconnect the battery.

- Remove the intake hose, air filter housing (diesel engines and some gasoline engines) and the battery.

On vehicles with 6-cyl. gasoline engine, battery is in the luggage compartment, accordingly only the air filter housing with the bracket must be removed.

- Remove the battery carrier.

- Place sufficient lint-free cloths in the area of the engine and transmission.

- Extract as much brake fluid as possible from the brake fluid reservoir with the (VAS 5234).

Vehicles with Manual Transmission

- Disconnect the clutch slave cylinder return hose - B - and secure it out of the way or clamp it off with a commercially available tool such as the Ha 4590 and then remove it.






All Vehicles

- Remove the connector - A - from the brake fluid level warning switch (F34).

- Pull off connector - C - from brake lamp switch (F).

- On vehicles with HBV, pull off connector from brake booster vacuum sensor (G483).

- Pull vacuum hose out of brake booster.

Vehicles with Manual Transmission

- Loosen the cables - 1 -, remove the bracket - 2 - and move it to the side.






Vehicles with Automatic Transmission 09G

On this automatic transmission, the ATF cooler is located directly in front of the brake booster, see following illustration.






- Mount the (10 - 222 A) and support the engine/transmission. Do not lift the transmission.

- Remove the noise insulation tray.

- Remove the pendulum support, first - A -, then - B -.






When installing, tighten - B - first and then - A -; tightening specification.

- Pry off the selector lever cable, remove it from the mounting bracket and retainer and lay it aside.

- Open the cable channel, pull the wiring harness for Servotronic out, then remove the cable channel from the console and lay it aside.

- Remove both bolts from the transmission bracket to the vehicle.

- Slightly lower the engine and transmission using the (10 - 222 A) spindle.

- Remove the vacuum hose - 2 - from the vacuum pump - 1 -.






- Remove the bracket for a wiring harness from the vacuum pump - 1 -.

Vehicles with Automatic Transmission 09M

- Open the cable channel, pull the wiring harness for Servotronic out, then remove the cable channel from the console and lay it aside.

- Pry off the selector lever cable, remove it from the mounting bracket and retainer and lay it aside.

- Remove the retainer from the selector lever cable.






All Vehicles

- Unfasten the brake lines at brake master cylinder and plug brake lines with sealing plugs from repair kit Part No. 1H0 698 311 A.

Also on vehicles with a 6-cylinder gasoline engine:

- Remove the nuts for the brake master cylinder.

- Carefully remove master brake cylinder from brake booster as well as heat shield.

- Remove brake booster vacuum sensor. Refer to => [ Brake Booster Vacuum Sensor (G483) ] Brake Booster Vacuum Sensor (G483).

- Remove the footwell cover on the driver side.

- Remove the nuts - arrows - and remove foot well trim - 1 -.






- Disconnect brake pedal from the brake booster. Refer to => [ Brake Pedal, Separating from Brake Booster ] Brake Pedal, Separating from Brake Booster.

- Remove the nuts - 1 - from the brake booster.






- Loosen both upper nuts - 2 - from the mounting bracket.

- Carefully remove the brake booster from the vehicle.

- Remove the nuts for the brake master cylinder.

- Carefully remove the brake master cylinder from the brake booster.

Installing

- Install in reverse order of removal.

Observe the following points when installing:

- Attach the brake pedal to the brake booster. Refer to => [ Brake Pedal, Attaching to Brake Booster ] Brake Pedal, Attaching to Brake Booster.

- After installing, bleed the brake system and clutch. Refer to => [ Hydraulic System, Bleeding ] Hydraulic System, Bleeding.